Conventional automatic transmissions employ an assembly commonly referred to as a “park system”, which is designed to perform a variety of park-related functions for the automatic transmission. For example, park system functionality may include positive gear shift selection, manual valve positioning, and/or park pawl activation or setting for locking the automatic transmission into a “park” position or parking gear setting. While vehicles are also provided with a separate parking brake preferable for use in locking a vehicle into a park setting on a relatively steep incline, when parking a vehicle on minimal slopes or relatively flat terrain, the parking pawl of a park system generally provides sufficient parking gear retention capability.
In addition to the parking gear, park pawl, and various related valve bodies, manual valves, and/or actuators used to set or position the park pawl, a park system typically includes a rotatable detent lever having a plurality of detent teeth. The detent lever moves in response to rotation of a manual shaft which is connected to the detent lever, with the detent teeth moving an actuator via an interconnected linkage or actuator rod to thereby set the park pawl. To properly position and/or bias the detent lever, a detent spring may be employed, with the detent spring being connected to a roller on one end. The roller in turn rolls along in contact with the contours or side surfaces of the various detent teeth of the detent lever in response to rotation and/or vertical motion of the detent lever, with the detent spring in turn flexing or deflecting as needed to properly bias the roller with respect to the detent teeth.
Typically, a park system is located or positioned to the exterior of the transmission case. However, such a configuration having a conventional detent spring as described above may be less than optimal for certain purposes and in certain positional respects. For example, tolerance or space allocation issues resulting from use of a conventional detent spring may result in interference within the crowded confines of a modern transmission case or housing, such as between the detent spring and a transmission oil pan or fluid reservoir. Such tolerance concerns may render assembly within the transmission housing particularly challenging, and may lead to unwanted contact between the detent spring and the oil pan during normal vehicle operation. Additionally, conventional detent spring configurations and attachment methods may not optimize the alignment or minimize the positional variance of the detent roller and the various detent teeth of the detent lever.